Treating Herpes May Prevent HIV Transmission

Everyone takes shortcuts--even medical researchers. That's not necessarily a bad thing. After all, where would we be if Christopher Columbus hadn't decided to take a shortcut to Asia? Hmm, maybe that's not the best example.

The point is that the best health-and-science journalists, like Alice Chang of the Associated Press, tell you right away when scientists are taking shortcuts.

Chang reported on a study that concluded that treating genital herpes might prevent transmission of the AIDS virus in people who are infected with both herpes and HIV. This makes sense since doctors already know that folks who are infected with herpes, or another sexually transmitted disease, are at greater risk of getting infected with HIV as well if they are exposed to the AIDS virus.

Near the very top of her article, Chang makes this important point:

In the latest study, conducted in Africa and published in Thursday's New England Journal of Medicine, women who took the herpes drug valacyclovir had less HIV in their blood and in their genital secretions.

The study did not look at whether the drug, sold as Valtrex by GlaxoSmithKline PLC, actually reduces transmission of the AIDS virus. However, scientists generally have found that the more virus someone has, the greater the risk of transmission.

In other words, the study investigators didn't measure whether the women in the study group actually passed on the virus less frequently than their untreated counterparts--that would have taken far too long and would have exposed more people to HIV. Rather the researchers measured the amount of HIV in the women's bloodstream and inferred that because the HIV levels dropped in the treated women, their risk of passing on HIV to someone else had fallen as well.

The researchers' assumption is reasonable but there is a chance it is mistaken. And that's why calling it to your attention, as Chang did, is a sign of good journalism.